1. Field of the Invention
The present invention relates to an outboard motor.
2. Description of the Related Art
An outboard motor is provided with an outboard motor body and a steering axle. The steering axle is attached to a boat. A rudder angle of the outboard motor is changed by rotating the outboard motor body centered on the steering axle. That is, a propulsion direction of the boat is changed.
The outboard motor body is attached to the steering axle via a bracket. Specifically, a casing is provided in the outboard motor body and the bracket is attached to the casing via a damper member. For example, as disclosed in Japanese Laid-open Patent Application Publication No. 2006-312379. the damper member has a substantially cylindrical shape and extends in a front-back direction of the outboard motor body. The damper member attenuates vibration transmitted from the outboard motor body to the boat. In addition, the damper member receives a load in the front-back direction of the outboard motor due to the weight of the outboard motor body or a propulsion force which is generated by a propeller. In addition, a load is received in the left-right direction of the outboard motor in addition to the load in the front-back direction of the outboard motor due to the propulsion force when the outboard motor is being steered while moving.
In order to attenuate vibration which is transmitted from an engine to a boat, it is preferable that the damper member be flexible. However, there is a problem in that control stability of the outboard motor decreases as the flexibility of the damper member increases. That is, when a boat operator turns a rudder of the boat, a rudder angle of the outboard motor reaches a rudder angle which is a target angle at a timing which is delayed from that intended by the boat operator. As the delay time increases, the control stability decreases. When a turning operation of the outboard motor is carried out, the damper member receives a load in the left-right direction. At this time, since the amount of change in the shape of the damper member increases as the flexibility of the damper member increases, the delay time during steering increases. In particular, during high-speed movement, since the load increases in the left-right direction which is received by the outboard motor during steering, the decrease in the control stability of the outboard motor is particularly significant and problematic.